Sometimes you get a map that's just not suited for Liberty. Playing a standard-size standard-speed Emperor oval map...
Get used to this. On deity, 9 out of 10 maps make liberty ill-suited at best, suicidal at worst. They get a second city planted within 5 turns, which
usually doesn't forward settle you too much, but they often have a third city in the first 40 turns that often boxes you in pretty well. Real estate is slim pickings quickly.
Now I have to decide whether to settle down into a peaceful (mostly) game, or raze KarTuku-something because it's too close to my city, capture Nineveh, then liberate that Spanish city he took so everybody will overlook my warmongering. That will leave Assyria in the game with one city and no military; let someone else eliminate them.
I'm not sure how this would play out naturally (i.e. without your intervention) on emperor level, but on Deity there's a (subjectively) better way to handle it. If Assyria is taking Spanish cities, he's likely beyond the breaking point where he can and will exterminate them completely. If you declare war (or play possum and let him DoW you), leave him with no army and capture one of his cities, you remove his ability to eradicate Spain, which would have worked to your favor as you could then liberate ALL the Spanish cities, and have the rest of the world rejoice at your presence despite planning on a conquering spree all along. Also means that Spain will vote any way you want her to for the rest of the game, if that factors in at all.
My social policies so far have been Honor (right side), Patronage opener, Consulates, Philanthropy, Scholasticism, Honor (left side). I'm allied to about a half a dozen CS's; they are making more science for me than my own cities are, but that will change in a few turns when I finish building my universities (especially at Sparta because it's surrounded by jungle.) Next policy I have to choose between opening Rationalism and Commerce. I think I need the gold more than I need beakers at this point.
Nice, I'm playing a lot of unconventional SP-pathing myself right now. The universally accepted best option would be rationalism, even if it seems like gold is more important to you at the moment, because it will allow you to more quickly get banks, stock exchanges, more trade routes, etc. But again, I applaud unconventional play and like switching things up. If it seems like your economy is a high priority to address and you want to try some unconventional SP-pathing, you might consider Piety
IF 1.) you have a religion or will get one before they're all gone, and 2.) there's still a reformation belief available that will help you, most likely TTGG (although some swear by JE, I don't care for it myself, plus TTGG solves another problem you'll encounter later - discussed below.) You're at the point in the game where the civs that went piety have already selected their reformation belief - go to the diplomacy screen and look under "Global Politics" to see which civs went piety, then check the religion screen to see which reformation beliefs they took. Process of elimination tells you what's left.
Piety is VERY good for the economy, arguably equal (or near) commerce. Looking at commerce - the opener is good with +25% in your capital. Wagon trains might be mediocre if you have lots of roads, meh if you don't. Mercenary army doesn't affect your economy. Entreprenuership is a negative social policy. Mercantilism helps with purchasing, which you won't be doing if your economy needs help. Protectionism is awesome for happiness, but you haven't mentioned struggles with this. And the finisher is good if you have lots of TP's, but not if you don't. Comparatively, Piety gives the same bonus the Commerce opener gives, but in ALL your cities instead of just the capital: you get a 25% bonus in all cities with a temple, and since temples are 1/2 the hammers, you will have them in all your cities. Furthermore, holy sites have +3 gold, and you'll probably want a couple of those. If you're planning aggression, which it sounds like you are, you're likely to capture at least a few more full Prophets for more holy sites, and this will help you with culture as well. Plus there's some added faith. Plus, it solves a big problem you're going to face later in the game - by going Honor and Patronage, the only great people you're qualified to purchase with faith are generals, and they won't be that helpful. If you can still snag TTGG, faith can go a long way between scientists, engineers, writers, and artists.